FR2792768A1 - LIMITING CIRCUIT BREAKER COMPRISING AN AUXILIARY ENERGY ACCUMULATOR - Google Patents

Abstract

A low voltage limiter circuit breaker comprises a fixed contact member and a movable contact member 50 itself comprising a support 58 pivoting about a fixed axis 60 between a closed position and an open position, a contact finger 62 pivoting about a fixed axis 64 between a non-repulsed position and a repulsed position, and a bistable device 80 comprising a spring 82 disposed between the support 58 and the finger 62. When the finger 62 is positioned in its repulsed position and the support 58 pivots from its closed position to its open position, it drives the finger 62 into its non-repulsed position. Part of the energy required to pass the neutral point of the bistable device 80 is supplied by a spring 92 which returns the support 58 to its open position only at the start of opening, which makes it possible not to oversize the spring. opening of the circuit breaker.

Description

LIMITING CIRCUIT BREAKER COMPRISING A BATTERY

AUXILIARY ENERGY

  The invention relates to a low-voltage limiting circuit breaker, and more particularly to a high-caliber low-voltage limiting circuit breaker. Document GB-A-1 564 412 describes a high-caliber low-voltage limiting circuit breaker, comprising * a housing; e an opening mechanism comprising at least one energy accumulator * one or more poles each comprising: * a contact member fixed relative to the housing; * a fixed stop relative to the housing; * a movable contact member comprising: e a movable support relative to the housing between a closed position and an open position; * at least one movable contact finger relative to the support between a non-repulsed position and a repulsed position; * at least one bistable mechanism comprising a spring arranged between the support and the finger so that it passes through a maximum of potential energy when the finger and the support are located in a neutral position relatively to one other, that it tends to recall the finger to its repulsed position when the finger is located relative to the support between its repulsed position and the neutral position, and that it tends to recall the finger to its non-repulsed position when the finger is located relative to the support between its non-repulsed position and the neutral position; the stopper being arranged in such a way that when the finger is positioned in its repulsed position and the support passes from its closed position to its open position, the finger, once in contact with the stopper, remains in contact with that -this until the support exceeds an intermediate tilting position relative to the housing, corresponding to the relative neutral position relative to the finger, the opening mechanism being kinematically linked to the support so as to return the support towards its open position when the support is in its

closed position.

  The spring of the bistable device combines several functions. It is intended first of all to ensure a contact pressure between the fixed contact member and the contact finger when the circuit breaker is closed, which is relatively independent of the state of wear and the manufacturing tolerances of the circuit breaker. This contact pressure is also decisive for the repulsion threshold beyond which the electromagnetic forces will drive the finger towards its repulsed position. When the finger has pivoted beyond neutral, the spring also serves to confirm the repulsion and / or to prevent a rebound of the finger, since it prohibits the return of the finger to the non-repulsed position. Before being able to close the circuit breaker again, it is therefore necessary to release the energy accumulator from the opening mechanism, which drives the bar and with it the support of the movable contact member in the open position, and which allows the

  finger to pivot in the non-repulsed position by cooperation with the stop.

  In such a device, the energy accumulator of the opening mechanism must overcome the resistance of the spring of the bistable device. However, this passage should preferably be made at the start of the opening stroke, in order to limit the size of the circuit breaker compartment where the contacts are located. As for the support, it must pivot quickly enough, on passing from the intermediate tilting position, so that the return force of the spring of the bistable device does not give rise, after the

  transition from neutral to a significant approximation between the finger and the fixed contact.

  Consequently, the spring of the opening mechanism must simultaneously accelerate the support and compress the spring of the bistable device. In terms of energy, it must simultaneously supply the spring of the bistable device with the energy necessary for it to reach its state of maximum potential energy, and provide the support

  the kinetic energy necessary for its rapid displacement towards the open position.

  Also remember that the spring of the opening mechanism must also ensure

  only the rapid opening of the circuit breaker in the event of tripping on low overcurrent.

  To reconcile these constraints, a powerful opening energy accumulator is generally provided. However, this solution is not without drawbacks, since the energy released during the opening must be dissipated in the opening end-of-travel stops, so that the power of the spring is decisive for the cost and the bulk. of the circuit breaker. In addition, it is necessary to provide different opening mechanisms depending on the number of poles of the circuit breaker. Recall that we meet not only monopolar, tripolar and quadrupole circuit breakers, but also, for high ratings where each phase is connected to two poles

  in parallel or in series, hexapolar or even octopolar circuit breakers.

  The dimensioning problem is even more complicated when identical mobile contact members, using identical supports, fingers and bistable devices, are intended to equip circuit breakers whose opening mechanisms are of a different nature. We would indeed like to be able to equip a range of circuit breakers equally with a first type of mechanism in which the energy accumulator of the opening mechanism also releases the energy necessary for closing the circuit breaker, and with a second type of mechanism, called OFO (for open, closed, open) in which a closing energy accumulator is armed regardless of the position of the contacts and ensures the arming of the opening energy accumulator simultaneously during closing. However, the two types of mechanism have different opening kinematics. It is thus generally considered that, for a given opening energy - that is to say for a given opening spring - the O-F-O mechanism is slower at the start of the stroke

  and faster at the end of the opening stroke.

  The invention therefore aims to remedy the drawbacks of the state of the art, and in particular to allow the use of mobile contact members with identical bistable mechanisms for limiting circuit breakers whose opening mechanisms have variable characteristics, in particular in opening race start. It also aims to allow a dimensioning of the opening mechanism of a limiting circuit breaker, independent of the number of poles. Another objective of the invention is to make the acceleration at the start of the opening stroke of the support of a movable contact member relatively independent of the type of opening mechanism used. Another objective of the invention is to limit the energy to be dissipated at the end of the opening stroke, without significantly increasing either the opening stroke or the size of the device. Another objective is to minimize the energy required

when opening.

  According to the invention, these objectives are achieved by means of a circuit breaker of the preceding type, in which each pole further comprises an auxiliary mechanism comprising one or more energy accumulators recalling the support towards its open position over all or part of the travel of the support between its closed position and the intermediate tilting position, but no longer beyond the intermediate tilting position. It is then possible to adjust the acceleration at the start of the race

  opening by judiciously choosing the power of the second accumulator.

  Preferably, the energy accumulator or accumulators of the auxiliary mechanism do not act on the support when the latter is between its intermediate tilting position and its open position. Beyond the tilting position, the support does not need a lot of energy to reach its open position,

  so that the contribution of the second accumulator is no longer necessary.

  Alternatively, it is possible to provide an accumulator supplying energy to the support over at least part of its travel between the closed position and the intermediate tilting position, and storing energy over at least part of the travel of the support between the intermediate position and the open position. This accumulator may for example comprise a spring whose rest position corresponds to the relative tilting position, acting in compression below and in traction beyond. This makes it possible to further limit the energy remaining to be dissipated in the end of travel stops of the opening mechanism at the end of the opening travel. Preferably, the energy accumulator or accumulators of the auxiliary mechanism of each pole are such that when the mobile support of the pole in question is displaced, they release an energy greater than or equal to that necessary to bring the at least one

  bistable mechanisms of the pole considered up to their maximum potential energy.

  This arrangement is particularly advantageous for a multipole circuit breaker comprising a control mechanism common to all of the poles. Indeed, it is then even easier to size the opening spring independently of the

  number of poles, while limiting its power.

  According to one embodiment, the circuit breaker further comprises hooking means. This arrangement promotes the transition from the intermediate tilting position to the open position. It therefore makes it possible to limit the kinetic energy necessary for the passage from the intermediate tilting position. This therefore makes it possible to limit the power of the auxiliary mechanism and also limits

  the energy to be dissipated in the opening end-of-travel stops.

  According to a preferred embodiment, the energy accumulator (s) of the mechanism

  each have a spring disposed between the housing and the support.

  Alternatively, it would naturally be possible to cause the auxiliary accumulators to act indirectly on the support, for example on an intermediate part of the kinematic transmission chain connecting the energy accumulator of the opening mechanism to the support. However, the preferred embodiment offers the advantage of limiting the constraints on this kinematic chain. Advantageously, the housing comprises polar compartments each containing one of said poles, the spring of each energy accumulator of the auxiliary mechanism of each pole being

  arranged in the corresponding polar compartment.

  According to one embodiment, the spring is a compression spring disposed inside a cylinder closed by a piston head capable of coming into contact with the support and transmitting to it the force of the compression spring. Alternatively, other types of springs can be envisaged, for example torsion springs or

bending.

  Other advantages and characteristics of the invention will emerge from the description which

  will follow from an embodiment of the invention, given by way of nonlimiting example and shown in the appended drawings in which: * FIG. 1 represents a sectional view of a circuit breaker according to the invention, in the closed position not repulsed; * Figure 2 shows in section the circuit breaker of Figure 1, in the closed position, partially repulsed, when passing through neutral; * Figure 3 shows in section the circuit breaker of Figure 1, in the closed, repulsed position; * Figure 4 shows in section the circuit breaker of Figure 1, in an intermediate tilting position; * Figure 5 shows in section the circuit breaker of Figure 1, in the open position * Figure 6 shows in a cutting plane parallel to that of Figure 1, a latching mechanism in a position corresponding to the closed position

repulsed from Figure 3.

  With reference to FIGS. 1 to 5, a high-caliber low-voltage multi-pole limiting circuit breaker 10 comprises a housing 12 divided into a front compartment 14 and a rear compartment 16 by an intermediate wall 18. A window 20 formed in the intermediate wall allows communication between the front compartments

and later.

  The front compartment 14 serves as a housing for a control device 22, which comprises a closing mechanism with energy accumulation 24 and an opening mechanism 26. This device is known per se and reference will be made to the document for more details. FR-A-2 589 626. It will suffice to recall here that the opening mechanism 26 comprises a toggle device which comprises two links 28, 30 articulated to one another by a pivot axis 32, the link lower 30

  of transmission being coupled to a crank 34 of a switching rod 36.

  An opening spring 38 is anchored between the crank 34 and a fixed cleat of

deduction 40.

  The rear compartment 16 serves as a housing for the switching bar 36 and for a plurality of poles 42 arranged side by side along a pivot axis 44 of the switching bar 36, in elementary compartments separated by substantially parallel watertight partitions in plan of Figures 1 to 5. Each pole 42 comprises a fixed contact member 46 connected to a connection pad 48, a movable contact member 50 connected to a connection pad 52 and an arc extinguishing chamber 54 provided of metallic separators 56. The movable contact member 50 comprises a movable support 58 mounted pivoting about a geometric axis 60 fixed relative to the housing, and a contact finger 62 pivoting around

  a geometric axis 64 fixed relative to the housing, and eccentric relative to the axis 60.

  i5 A connecting rod 66 ensures the coupling of the support 58 to the switching rod 36.

  One end of the finger 62 supports a contact pad 68 intended to ensure the

  contact with a contact pad 70 supported by the fixed contact member 46.

  The other end of the finger 62 constitutes a cam 72 with two ramps 74, 76 on either side of a top dead center 78. Between the support 58 and the finger 62 is disposed an elastic energy accumulator, comprising a spring 82 guided in a cage 84 and pushing out a rod 86 supporting a rotary roller 88 therefrom. The roller 88 is thus permanently in contact with the cam 72. The elastic energy accumulator

  constitutes with the cam 72 a bistable mechanism 80.

  Between the housing 12 and the support 58 is disposed an auxiliary elastic energy accumulator 90, visible in its relaxed state in FIG. 5, and comprising a compression spring 92 tending to push towards the support 58 a head 94 guided in translation in a cylinder 96 fixed relative to the housing 12. The front part of the head 94 comprises a bead 98 intended to cooperate radially with the cylinder to ensure the guidance, and axially with a flange 100 partially closing the

  cylinder and forming limit stop.

  A hooking device 102, visible in detail in FIG. 6, comprises an arm 104 pivoting about a fixed axis 106 and elastically recalled, clockwise in the figure, by a torsion spring 108. A movable stop 110 is located at the end of the arm 104 and cooperates with a stepped surface 112 of the finger 62. The arm has in

  in addition to a lug 114, capable of cooperating with a cam 116 located on the support 58.

  The intermediate wall 18 supports an end-of-travel stop 118 made of elastomeric material.

  The operation of the device is as follows.

  In the closed position of FIG. 1, the contact pads 68, 70 are in contact with each other and ensure the closing of the electrical circuit between the connection pads 48, 52. The spring 82 of the bistable mechanism 80 is compressed and the roller 88 cooperates with the ramp 74 so as to ensure a contact pressure between the pellets 68, 70. In the presence of an overcurrent, the electromagnetic forces tend to rotate the finger 62 around its axis clockwise in the figures, and the bistable mechanism 80 tends to oppose this pivoting. When the intensity of the current exceeds a limitation threshold corresponding to the calibration of the spring 82, the finger 62 pivots and passes the neutral point 78 of the bistable mechanism 80, shown in FIG. 2. Once this neutral point has passed, the roller 88 cooperates with the ramp 76 and contributes to pushing the finger 62 towards the end of travel stop 118, up to the position of FIG. 3. The stop 118 plays the role of a shock absorber and

  allows, by absorbing the excess kinetic energy, to avoid a rebound of the finger 62.

  The stop 110 of the hooking device 102 pivots under the stress of its return spring 108 and remains in contact with the stepped surface 112 of the finger 62, so

  that the hooking mechanism 102 prohibits the return of the finger 62 to the low position.

  To be able to close the circuit breaker, it is first necessary to carry out an opening operation by the control mechanism. An opening lock, actuated by an operator or a trigger, releases the linkage 28, 30, 32. The opening spring 38, assisted by the springs 92 of the auxiliary accumulators 90 of each pole, drives the switching bar 36 rotating counterclockwise and, through the connecting rod 66, rotate the support 58 about its axis 60 clockwise from the position of Figure 3 to the position of Figure 4 then continues alone to urge the bar 36 until is

  reached the position of figure 5.

  Between the position of Figure 3 and that of Figure 4, the roller 88 cooperates with the ramp 76 and applies to the finger 62 a force whose moment tends to rotate the finger 62 clockwise around the axis 64 The damper 118 then acts as an end of travel stop, so that the finger 62 remains stationary; It is therefore the roller 88 which disappears by compressing the spring 82. In this phase, the auxiliary energy accumulator 80 of each pole repels the corresponding support 58. The head 94 of the auxiliary accumulator 80 reaches its end-of-travel position when the support 58 reaches the intermediate tilting position of FIG. 4, so that

  the contact between the head of the auxiliary accumulator and the support ceases.

  Beyond this intermediate tilting position, the roller 88 urges the ramp 74. The movement of the finger 62 counterclockwise is however counteracted by the stop 110 of the latch 102, so that the finger 62 remains relatively immobile, apart from the mounting clearance. The action of the opening spring 38 and that of the spring 82 of the bistable mechanism combine and cause the support 58 clockwise to its high position in FIG. 5. In an intermediate position between the position in FIG. 4 and that of FIG. 5, very close to the latter, the cam 116 of the support 58 pushes back the lug 114 of the arm 104, so that the latter pivots anticlockwise and releases the stop 110. However, this release does not cause significant pivoting of the finger 62 in the anticlockwise direction, because the movement of the

  support 58 is then practically completed.

  From the position of FIG. 6, the closing can be triggered by action on a closing latch which releases a closing spring, pivoting the switching rod from its position in FIG. 6 to its closed position in FIG. 1 The bar 36 drives the support 58 anti-clockwise and the finger 62, urged only by the roller 88 which follows the movement of the support 58, is also driven. The support 58 compresses and recharges the spring 92 of the auxiliary accumulator 90 at the end of the closing stroke. this allows

  incidentally to limit the impact at the end of the closing stroke.

  By way of simplification, the invention has been described by considering that each pole comprises a single contact finger 62, a single bistable mechanism 80 and a single auxiliary accumulator 90. In practice, it may be advantageous to provide a plurality of fingers per pole, for example three or five identical fingers pivoting about a common axis 64. Each finger must then be stressed by a bistable mechanism, which can be common to several fingers or independent for each finger, so that each finger is stressed by a different spring. The support 58 remains unique for each pole. Depending on the size of the support 58, in particular its width in a direction perpendicular to the plane of the figures, it may be advantageous to provide an auxiliary accumulator 90 comprising several springs arranged in parallel. In practice, three springs arranged in parallel and each acting on a

  different head, allow to obtain interesting dimensional characteristics.

  In practice, it is advantageous to size the auxiliary accumulators so that they release together when they relax an energy greater than that

  necessary to compress the spring of the bistable mechanism.

  Naturally, the invention is not limited to the embodiment described above.

  Various modifications are possible within the scope of the invention.

  In the previous example, the latching mechanism 102 performs two functions: on the one hand, it acts as an anti-rebound, in the sense that it avoids, in the event of a very high intensity short circuit generating significant electrodynamic forces , that the finger, arrived in the position of FIG. 3 and coming to strike violently the shock absorber 118, does not rebound and does not come back to close the contact; moreover, it prevents the pivoting of the finger 62 during opening, when the support 58 has just exceeded the intermediate tilting position. However, depending on the size of the circuit breaker and the size of the mechanical parts, it can be envisaged to eliminate this latching mechanism. The anti-rebound function is then assumed exclusively by the bistable mechanism 80, assisted if necessary by the end-of-travel damper 118. As for the movement beyond the intermediate tilting position, it can be limited in its extent to become imperceptible, if the speed of the

  support 58 when passing from the tilting position is sufficient.

  In the embodiment described, the stop 118 performs two functions, it serves on the one hand to anti-rebound since it absorbs part of the kinetic energy at the end of travel of the finger 62 towards its repulsed position; it also makes it possible to immobilize the finger 62 when the support 58 pivots from its closed position to its intermediate tilting position. According to an alternative embodiment, these two functions can be performed by different bodies. A finger repulsion end-of-travel stop may for example be disposed on the support 58, and an independent stop disposed on the housing. This arrangement makes it possible to lift the support 58 and the finger 62 repulsed together in a first part of the travel of the support 58 towards its open position, before the finger 62 meets the stop of the

  casing and does not come to a standstill therein.

  The invention has been described with reference to a limiting circuit breaker whose fingers pivot around a geometric axis 64 fixed relative to the housing. However, it is also applicable to a limiting circuit breaker as described for example in document GB-A-1 564 412, the fingers of which pivot about a fixed axis with respect to O10 to the pivoting support itself around a fixed axis relative to the housing, and offset by

compared to the previous one.

  The switching bar 36 and the support 58 may constitute a single piece, in which case the connecting rod 66 disappears and the linkage 28, 30, 32 of the control mechanism is directly articulated by one of its ends on the support. This

  configuration corresponds to the mechanism of document GB-A-1 564 412.

  The invention is applicable regardless of the type of opening mechanism and

closing of the circuit breaker.

1l

Claims (7)

  1. Low-voltage limiter circuit breaker (10) comprising * a box (12); * an opening mechanism (26) comprising at least one energy accumulator (38); * one or more poles (42) each comprising: * a fixed contact member (46) relative to the housing; * a fixed stop (118) relative to the housing; e a movable contact member (50) comprising: * a support (58) movable relative to the housing between a closed position and an open position; * at least one contact finger (62) movable between a non-repulsed position and a repulsed position relative to the support; e at least one bistable mechanism (80) comprising a spring (82) disposed between the support and the finger so that it passes through a maximum of potential energy when the finger and the support are located in a neutral position relatively to each other, that it tends to recall the finger to its repulsed position when the finger is located relative to the support between its repulsed position and the neutral position, and that it tends to recall the finger to its non-repulsed position when the finger is located relative to the support between its non-repulsed position and the neutral position; the stop (118) being arranged in such a way that when the finger (62) is positioned in its repulsed position and the support (58) passes from its closed position to its open position, the finger (62), a once in contact with the stop (118), remains in contact with the latter until the support exceeds an intermediate tilting position relative to the housing, corresponding to the relative neutral position relative to the finger, the mechanism d the opening (26) being kinematically linked to the support (58) so as to return the support to its open position when the support is in its closed position; characterized in that each pole (42) further comprises an auxiliary mechanism comprising one or more energy accumulators (90) returning the support (58) to its open position over all or part of the travel of the support between its position closing position and the intermediate tilting position, but no longer beyond   from the intermediate tilting position.   2. Circuit breaker according to claim 1 characterized in that the energy accumulator (s) (90) of the auxiliary mechanism do not act on the support (58) when the latter is between its intermediate tilting position and its position d 'opening. 3. Circuit breaker according to claim 1 characterized in that the energy accumulator (s) (90) of the auxiliary mechanism of each pole (42) are such that during the movement of the support (58) of the pole considered, they release a higher energy or equal to that necessary to bring the bistable mechanism (s) (80) from the pole   considered up to their maximum potential energy.   4. Circuit breaker according to claim 1 characterized in that it further comprises attachment means (102).   5. Circuit breaker according to claim 1 characterized in that the energy accumulator (s) (90) of the auxiliary mechanism each comprise a spring (92) disposed   between the housing (12) and the support (58).   6. Circuit breaker according to claim 5, characterized in that the housing (12) comprises pole compartments each containing one of said poles (42), the spring (92) of each energy accumulator (90) of the auxiliary mechanism of each pole   being arranged in the corresponding polar compartment.   7. Circuit breaker according to claim 6, characterized in that the spring (92) of each energy accumulator (90) of the auxiliary mechanism is a compression spring arranged inside a cylinder (96) closed by a head piston (94) capable of coming into contact with the support (58) and transmitting to it the force of the compression spring.